Alloy for turbine blades



Toatlwlwmit 1,481,782 PATENT OFFICE.

rrxno mm, 01' SUGAIOLOHI, urn.

Armor For. mm.

In Drawing.

concern.

Be it known that I'rrno Imam, a sub'ect of the Emperor of Japan residing at o. 26, Sanchome Sugamomac i, Toyko Prefecture, Japan, has invented certain new and useful Im rovements in Alloys for Turbine Blades, 0 which the following is a specification.

This invention relates to an alloy for turbine blades, containing copper, alunnnium, nickel and iron in special percentages. The object of the invention is to produce an allo which has a remarkable resistance to oxi 'tion and also to atmospheric and sea water corrosion, together with a high tensile strength and 'good elongation, and

particularly efiicient as a material for turine blades.

l-leretofore, allogs such as manganese cplzper, phosphor ronze, brass and nickel s etc., have been used for the material of turbine blades. The former three have tensile strengths of tons per square inch or less. Therefore, the strength of such alloys is not s cient for turbine blades of recent t rhinos in which the blade is subjects tdthe action of superheated steam of extremel high temperature and ressure. Nicke steel has a tensile strengt of tons per square inchr But this allo has small resisting power to oxidation an cor rosion. In the United States of America, the so called Monel metal is used to a at extent but th cost of this alloy is very igh as the content of nickel is exceedingly large.

If only one 'piece of the eat numberof vanes in a' turbine blade e broken, then man other vanes may become damaged and ally the turbineitself may be brought 1? w now proceed to -explain how the allo according to the invention is en erior to e known alloys for use in making turbine blades.

Acco d g to the invention, the content ited to 5 to 7%, and this is one igiportant features of the invention. A110 V escribed in Japanese Patents Nos.

' asses and 29068 somewhat resemble the present alloy, but the contain A1 of 7 to '12% which makes t e metallic structure of em gluit'e different from that of the I) lit a oy and thus makes them unrese suitable for the material of turbine blades.

This difl'erence is really due to a slight differenee of percentage of Al. It is a known centa used.

Application fled January 8, 1922. Berta! No. 527,884.

fact that when in an alloy, is contained in slight excess, it becomes a structure of alumin um bronze, its hardness increases, its elongation suddenly dec, and the rollin or drawing of it becomes very diflicult.

according to the invention, the perof Ni is limited to 3 to 8% and that ofFeto1to3%. ThesumofCuandAl 1s 90 to 96% and accordingl the sum of N1 and Fe to 4 to 10%, and at of Ni and A1 to 10 to 14%.

Of course, the method of manufacturing ingots of the new alloy, may be varied, but one exam la is as follows:

Any suitable type of furnace may be used which is'capable of readil erat' a temperature of 1400 de y Fdi' instance, a graphite crucib e furnace can be Copper is charged therein and is covered by charcoal. '1 e charge is heated and when the copper is melted, iron and nickel in the determined proportions are added. When the mixture is sufliciently melted, aluminium is added, also in prede tel-mined quantity, After a suitable agitation, the melted metal is cast into moulds. The meltin temperature is about 1300 degrees C. an the casting temperature is 1250 to 1300 degrees C.

Even an alloy having the above percent,

ages, can not become an excellent material for turbine blades unless it is subjected to the special heat treatment, quite different from theordinary process. First, the block of material for the turbine blade is repared from an ingot of alloy, the metho of preparing the ingot, however, being uite ordinary and convenient. This bloc is tempered by heating at a temperature of about 800 degrees C. for a few hours. Then the temperature is lowered to 500 to 700 degrees (3., and this state is maintained one to three hours. Then the block is somewhat.

Tiaving now particularly described and ascertained the nature of this invention and amen in whet manner the some istobe performed, proportions of 90 to 96% of cop er plus I declare what I claim is aluminium, 4 to 10% of nickel p us lIOIl An alloy for turbine blades, including and accordin 1y 10 to 14% of nickel plus 10 copper as the main constituent, and suboraluminium, su stantiall as set forth. dinnte constituents consisting of 5 to 7% In testimony whereo he afiixes his signaofeluminium, 3 to 8% of nickel, and 1 to 3% ture. of iron, and further characterised by the I ITYRO IYTA. 

